From 41adf3281ef6386c539f1fb9d36c4fb3f643b77c Mon Sep 17 00:00:00 2001
From: Eli Zaretskii <eliz@gnu.org>
Date: Tue, 31 Oct 2017 21:08:35 +0200
Subject: [PATCH] Avoid duplicate calls to xfree for the same pointer

* src/alloc.c (sweep_symbols): Avoid freeing an already freed
pointer to a symbol's buffer-local value.  (Bug#29066)
---
 src/alloc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/alloc.c b/src/alloc.c
index d9d74856799..11afdfd7cc0 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -7024,7 +7024,9 @@ sweep_symbols (void)
         {
           if (!sym->s.gcmarkbit)
             {
-              if (sym->s.redirect == SYMBOL_LOCALIZED)
+              if (sym->s.redirect == SYMBOL_LOCALIZED
+		  /* Already freed?  */
+		  && !EQ (sym->s.function, Vdead))
                 xfree (SYMBOL_BLV (&sym->s));
               sym->s.next = symbol_free_list;
               symbol_free_list = &sym->s;
-- 
2.39.2